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内容記述 |
Total reflection X-ray fluorescence (TXRF) analysis is typically utilized to analyze trace ele-ments. Our research group has employed this technique to analyze uranium in solution [1]. Dur-ing the TXRF analysis of a liquid sample, several microliters of the solution were dropped onto a fluorine-coated glass slide and dried. However, the sensitivity of the measurement can be im-proved by increasing the volume of the sample dropped onto the measurable area. In principle, a solution of the same concentration can be measured with tenfold sensitivity by dropping 10 times its volume onto the same spot size. In this study, we propose a more sensitive TXRF analy-sis method by applying a fluorine coating to the outside part of a hydrophilic slide glass, except for the central spot, which allows 1 mL of the solution to be dropped.The hydrophilic surface-treated glass slide was covered on one side with polyimide tape, and the outer tape was cut off, leaving a 6 mm diameter of making area in the center. Then, a fluororesin solution (Fine Chemical Japan Co., Ltd.) was sprayed onto the surface, and after drying, the masking tape was removed. The sample was prepared by diluting a multielement standardized solution of XSTC-4470 (Spex CertiPrep Inc.) containing 10 ng/μL of uranium, and 1 mL of this solution was dropped onto the hydrophilic spot of the glass slide. The dropped solution was evaporated under redused pressure to shrink onto a 6 mm-hydrophilic spot, followed by adding 10 μL of 1 ng/μL Ga solution as an internal standard, and then dried completely. All measure-ments were performed using a TXRF spectrometer NANOHUNTER-II (Rigaku Co., Ltd.), at a tube voltage and current of 50 kV and 12 mA, respectively.As illustrated in Figure 1, the solution on the fluorine-coated area shrinks to the hydrophilic spot during the drying process. This facilitates TXRF analysis with higher sensitivity than conven-tional methods.This study was performed under the auspices of the Secretariat of the Nuclear Regulation Authority, Japan.Reference[1] T. Matsuyama, et al., Frontier in Chemistry 7 (2019) 152. |
